Tydirium:
The desktop chite-map editor. Sadly still in a pre-alpha
state (I really must get round to finishing it sometime!)
Download Tydirium
(It's a 24K zip)

Quantize:
The desktop utility for producing lovely dithered gifs & sprites
with relatively few colours from sprites with a ludicrous amount
of colours. Also not really finished, but here it is...
Download Quantize
(It's a 22K zip)

QBuild:
The desktop utility set for creating new maps for Quake.
(NB - You'll need a StrongArm, and somewhere over 12Mb of ram to run this one!)
Download QBuild
(It's a 140K zip)

QInfo:
In the continuing absence of a completed full version of QBuild, I'm
sticking my Quake Entity notes here. It's a StrongHelp file will lots
of useful stuff.
Download QInfo
(It's a 24K zip)